<!DOCTYPE html>
<html lang="zh-CN">
<head>
    <meta charset="UTF-8">
    <title>多重条件</title>
</head>
<body>
<script>
    var myAge = parseInt(prompt('Enter your age', '30'), 10);

    if (myAge >= 0 && myAge <= 10) {
        document.write('my age is between 0 and 10<br/>');
    }

    if (!(myAge >= 0 && myAge <= 10)) {
        document.write('my age is NOT between 0 amd 10<br/>');
    }

    if (myAge >= 80 || myAge <= 10) {
        document.write('my age  is 80 or above 10 or bellow<br/>');
    }

    if ((myAge >= 30 && myAge <= 39) || (myAge >= 80 && myAge <= 90)) {
        document.write('my age is between 30 and 39 or my age is between 80 and 89');
    }
</script>
</body>
</html>